This analysis is based on data on US mass shootings 1982 - 2019 provided by Mother Jones.
The download is available on motherjones.com
Nevada has had the most victims from mass shootings, due to the 2017 Las Vegas Strip massacre in which there were 604 victims (546 injured, and 58 killed).
35 of the 50 states (70%) had at least one mass shooting between 1982 and 2019.
California has had the most mass shootings (19).
of mass shooters were men
The number of mass shootings per year in the US is increasing.
The year with the most shootings was 2018 which consisted of 11% of the mass shootings.
The number of mass shootings this decade is almost triple the number in the previous decade.
California and Texas have had mass shootings in every decade.
56% of mass shooters were white.
53% of mass shooters had prior signs of mental health issues.
72% of mass shooters obtained weapons legally.
A third of US mass shootings occurred in a workplace.
Shooter ages ranged from 11 to 66.
A third of mass shooters were in their 20s (34% of mass shootings).
There is a noticeable increase in recent years in the number of mass shooters in their twenties.
Note: The age bracket “1-12” has been excluded from the charts because there was only one instance in that category and so there is little use trying to illustrate the pattern over time for that age bracket.
Almost two thirds (65%) of mass shootings involved semi-automatic weapons.
Just over half (53%) of mass shootings involved multiple weapons.
The original breakdown of number of mass shootings by gender was:
| Gender | Shootings |
|---|---|
| F | 1 |
| Female | 2 |
| M | 36 |
| Male | 70 |
| Male & Female | 1 |
The cleansed breakdown is:
| Gender | Shootings |
|---|---|
| Female | 3 |
| Male | 106 |
| Male & Female | 1 |
The original breakdown of number of mass shootings by race was:
| Race | Shootings |
|---|---|
| 1 | |
| - | 2 |
| Asian | 8 |
| black | 9 |
| Black | 9 |
| Latino | 10 |
| Native American | 3 |
| Other | 5 |
| unclear | 1 |
| white | 41 |
| White | 21 |
The cleansed breakdown is:
| Race | Shootings |
|---|---|
| Black | 18 |
| Latino | 10 |
| Native American | 3 |
| Unknown | 17 |
| White | 62 |
The original breakdown of number of mass shootings by “Weapons Obtained Legally” was:
| Weapons Obtained Legally | Shootings |
|---|---|
| Yes | 2 |
| - | 1 |
| Kelley passed federal criminal background checks; the US Air Force failed to provide information on his criminal history to the FBI | 1 |
| No | 16 |
| TBD | 7 |
| Unknown | 6 |
| Yes | 76 |
| Yes (“some of the weapons were purchased legally and some of them may not have been”) | 1 |
The cleansed breakdown is:
| Weapons Obtained Legally | Shootings |
|---|---|
| No | 16 |
| Unknown | 15 |
| Yes | 79 |
A new column was added containing the state code e.g. CA for California.
In the original data, the unique states after the comma in the location column were:
| State | Shootings |
|---|---|
| Arizona | 1 |
| Arkansas | 1 |
| CA | 5 |
| California | 14 |
| CO | 1 |
| Colorado | 5 |
| Connecticut | 3 |
| D.C. | 1 |
| FL | 2 |
| Florida | 9 |
| Georgia | 2 |
| Hawaii | 1 |
| IL | 2 |
| Illinois | 2 |
| Iowa | 1 |
| Kansas | 1 |
| Kentucky | 2 |
| Lousiana | 1 |
| Massachusetts | 1 |
| MD | 3 |
| Michigan | 2 |
| Minnesota | 2 |
| Mississippi | 1 |
| Missouri | 1 |
| Nebraska | 1 |
| Nevada | 1 |
| New York | 4 |
| North Carolina | 2 |
| NV | 1 |
| OH | 1 |
| Ohio | 2 |
| Oklahoma | 1 |
| Oregon | 2 |
| PA | 3 |
| Pennsylvania | 2 |
| South Carolina | 2 |
| Tennessee | 1 |
| Texas | 7 |
| TN | 1 |
| TX | 2 |
| Utah | 1 |
| Virginia | 1 |
| Washington | 7 |
| Wisconsin | 4 |
After cleansing, the unique states are:
| State | Shootings |
|---|---|
| AR | 1 |
| AZ | 1 |
| CA | 19 |
| CO | 6 |
| CT | 3 |
| D.C. | 1 |
| FL | 11 |
| GA | 2 |
| HI | 1 |
| IA | 1 |
| IL | 4 |
| KS | 1 |
| KY | 2 |
| LA | 1 |
| MA | 1 |
| MD | 3 |
| MI | 2 |
| MN | 2 |
| MO | 1 |
| MS | 1 |
| NC | 2 |
| NE | 1 |
| NV | 2 |
| NY | 4 |
| OH | 3 |
| OK | 1 |
| OR | 2 |
| PA | 5 |
| SC | 2 |
| TN | 2 |
| TX | 9 |
| UT | 1 |
| VA | 1 |
| WA | 7 |
| WI | 4 |
The location types were:
| Location Type | Shootings |
|---|---|
| Workplace | 1 |
| Airport | 1 |
| Military | 5 |
| Other | 42 |
| Other | 3 |
| Religious | 6 |
| School | 17 |
| Workplace | 35 |
There were 2 instances of “Workplace”" as one had a leading white space.
There were also 2 instaces of “Other”" as one with a trailing white space.
The cleansed types are:
| Location Type | Shootings |
|---|---|
| Airport | 1 |
| Military | 5 |
| Other | 45 |
| Religious | 6 |
| School | 17 |
| Workplace | 36 |
The values in the imported data were:
| Prior Signs Of Mental Health Issues | Shootings |
|---|---|
| - | 7 |
| No | 17 |
| TBD | 3 |
| Unclear | 24 |
| Unknown | 1 |
| Yes | 58 |
The values are now:
| Prior Signs Of Mental Health Issues | Shootings |
|---|---|
| No | 17 |
| Unknown | 35 |
| Yes | 58 |